METHOD OF RECORDING A MULTI-LAYER OPTICALLY RECORDABLE INFORMATION CARRIER

摘要

The application relates to a method of and an apparatus for writing information onto a multi-layer optical information carrier (1). In an optical recording system, information can be written onto a selected layer (41) of a multi-layer carrier (1) by focusing the laser beam (2) onto the selected layer. Intermediate layers (42) interact with the laser beam (2). An important property in writing information onto a multi-layer carrier (1) is the transmission coefficient of these intermediate layers (42). The transmission coefficient depends on the physical properties of the intermediate layer (42) and on whether or not information has been recorded. The apparatus includes a circuit (55) which derives information (711) about the changes of the transmission coefficients of the layers (41 through 43) when information is written onto these layers. On the basis of this information (711) a circuit determines the sequence in which the layers (41 through 43) are to be recorded. The sequence can be selected so as to minimize the intensity of the laser beam (2), thereby precluding unnecessary heating of the carrier (1) and allowing comparatively simple and cheap laser beam sources (3) to be used.